The present invention relates to a hermetic compressor motor terminal, and in particular to such a terminal which will maintain the integrity of the seal between it and the compressor housing even under high overcurrent conditions.
Terminal assemblies for hermetic compressors are well known and generally comprise a cup-shaped metallic body member having a plurality of metallic conductor pins extending therethrough. In order to seal and electrically insulate the conductor pins relative to the body member, they are usually either potted in epoxy or sealed in glass. Both the inner and outer ends of the conductive pins may be provided with conductor tabs so as to facilitate connection to the external current source and to the compressor motor. Examples of such motor compressor terminals are disclosed in U.S. Pat. Nos. 4,059,325, 3,770,878, and 3,988,053.
One of the persistent problems with prior art electrical terminals for hermetic compressors is that when abnormally high overcurrent conditions exist, such as a ground fault or short circuit, the conductor pins melt, which allows the hot, high pressure gas and liquid from the compressor to discharge through the opening in the terminal assembly left by the melted conductor pin. Obviously, this is an extremely hazardous situation for persons in the vicinity of the compressor, because the gas and liquid will be ejected at high pressure.
Although attempts have been made to prevent shorting of the conductor pins by shielding them from contaminants produced during motor failure, this still does not solve the problem of preventing destruction of the seal in the event that overcurrent conditions are sufficiently large to cause melting of one or more of the conductor pins. The purpose of the present invention is to insure that the seal remains intact even during irreversible overcurrent conditions of sufficient magnitude to melt the normal diameter pins.